You might think that when you speak, you know exactly what you’re going to say, that your brain knows what words you’re uttering, and that when they come out of your mouth, people will hear exactly what your brain intended to communicate.

Unfortunately for you, according to science, that’s not true at all. It turns out that your brain only knows what you’re saying until after you hear yourself speak, meaning that “your speech” is somewhat reactionary to what you already said.

Cognitive scientists at Lund University in Sweden, led by Andreas Lind, asked participants to do a Stroop test ; they were asked to say a word, but then hear themselves utter a different world through headphones. After hearing the manipulated word, they were asked whether or not they detected the switch. When the manipulated word was played between 5-20 milliseconds of the participant starting to speak, the manipulation went undetected 85 percent of the time. The study was published in the latest issue of Psychological Science.

So what does this mean? Basically, you rely on your auditory feedback to know exactly what you said.

“When he put himself through the test, even he felt that the speech exchanges sounded convincing — even though he knew exactly when the manipulations were occurring. ‘When you say one thing but hear yourself clearly saying something else, it’s a very powerful feeling,’ he says.”

So next time you roll your eyes at a meeting and think to yourself “Man, that jackass is just rambling and doesn’t know what the f&%k he’s saying,” you might actually be right.